1. Field of the Invention
The present general inventive concept relates to a toner cartridge used with an electrophotographic image forming apparatus.
2. Description of the Related Art
An electrophotographic image forming apparatus such as a dry type color laser printer is an apparatus that forms an electrostatic latent image on a photosensitive medium, develops the image with a powder toner, and transfers the developed image on a document via a predetermined transfer medium to form an image. The image forming apparatus uses a photosensitive substance to develop the electrostatic latent image on the photosensitive substance, and includes a toner cartridge, which is a developing unit containing dry type toner.
Japanese Laid-open Patent No. 2001-255727 discloses an image forming apparatus including a developing device having a developing roller, and a toner cartridge supplying toner to the developing device. The toner cartridge is vertically disposed to supply the toner to a toner hopper in the developing device. Therefore, a printer including the above developing device has a large vertical volume.
In a dry type color printer having a compact structure, a toner cartridge is placed in a horizontal direction with respect to a developing unit and has a structure in which toner cartridges of different colors are vertically stacked.
FIG. 1 is a partial cross-sectional view illustrating a conventional toner cartridge supplying toner in a horizontal direction.
Referring to FIG. 1, a plurality of semicircular chambers 12 are sequentially formed at a lower portion of a housing 10, and each of the chambers 12 includes an agitator 14. A developing roller 20 is installed on a front end portion of the housing 10, and a toner supplying roller 30 is installed to contact the developing roller 20. A guide member 40 that receives the toner supplied from the agitator 14 and helps the toner attach on an outer circumference of the toner supplying roller 30 is disposed under the toner supplying roller 30. A recovery roller 50 that returns remaining toner, which is not supplied to the developing roller 20 from the toner supplying roller 30, toward the chamber 12 including the first agitator 14, is disposed under the guide member 40.
The toner supplying roller 30 rotates in the rotating direction of the developing roller 20 to clean the toner remaining on the surface of the developing roller 20 by contacting the developing roller 20, and supplies the toner onto the surface of the developing roller 20 by compressing the toner on the surface of the developing roller 20 immediately before contacting the developing roller 20.
A doctor-blade 16 is installed at the housing to remove excessive toner from the developing roller 20 in order to control the height of the toner on the surface of the developing roller 20.
The toner removed from the developing roller 20 by the doctor blade 16 and a toner passed through a toner path without being adhered to the surface of the developing roller 20 from the toner supplying roller 30 is returned to the first hopper 12 through a recovery hole 51 by the recovery roller 50.
A seal bracket 33 that covers the developing roller 20 and the supplying roller 30 and prevents the toner from being sealed outward is installed on an upper portion of the housing 10. A seal film 34 is adhered on the seal bracket 33 to prevent the toner between the developing roller 20 and the supplying roller 30 from exiting the housing 10, and to prevent external impurities from penetrating into the toner cartridge.
However, in the toner cartridge having the above structure, the toner may be stacked on the upper part of the developing roller 20 and the toner supplying roller 30 (portion A in FIG. 1). The toner stacked on the portion A interrupts the cleaning operation of the remaining toner of the developing roller 20 performed by the toner supplying roller 30. In addition, when the toner impacts the seal film 34 due to an external shock, the toner may leak through the seal film 34.